I’m new to Discourse. I’m running a trial instance with docs enabled. I can see the docs but I dont see how to add new docs. Can someone point me in the right direction please?
Hello and welcome @Yoni_Balkind 
You create topics as normal in either a category or with a tag you’ve added to the docs settings, and that will add them to your docs page. 
Hmm okay, so docs are not a different content type per se. Its just a “bucket” of sorts for topics that have a certain category.
Okay so if I may segue into a follow up questions: I see that there is a concept of Posts and this seems to be something different to Topics. But I can’t quite see how to submit a post. Is a Post simply a reply to a topic?
Docs have a special page and a slightly different layout, but are built from regular topics. You can check out ours here on Meta Docs - Discourse Meta. This is the docs version of one https://meta.discourse.org/docs?topic=224824 and this is the topic Trust Level Permissions Table (inc Moderator Roles)
A topic is a collection of posts linked together to make a conversation. This discussion we’re now having, for example, is a topic consisting of individual posts.